Pneumatic motor



NQV. 2l, 1939. E Vl, MONNlER I 2,180,993

PNEUMATIC MOTOR Filed July 50, 1957 a ,7. m53 /6 l o 54 5 1;

A TTORNE y Patented Nov. 2l, 1939 UNITED STATES; PATENT OFFICE y l `rismnixm'rio Moron Emory J; Monnier, Detroit, Mich. Application July 30,1937,l Serial No. 156,477 aclaiins. (01253-2).

1 The object of my invention is to provide a pneumatic motor of simple, durable and inexpensive construction.

A further object of my invention is to provide a pneumatic motor capable of exceptionally high speed operation. My improved motor is adapted to drive a small internal grinding, wheel at a peripheral speed sufficient-to give an eiiicient grinding operation. It isk well known in the grinding art that a surface or peripheral speed of between six and eight thousand feet per minute is necessary in order to produce an ecient grinding action. Consequently, when it is desired to finish the bore of small cylinders of from one-quarter or five-sixteenths of an inc-h in diameter, avery high speed of rotation is necessary to obtain the necessary six to eight thousand feet per minute peripheral speed.

In the manufacture of fuel pumps for Diesel type engines my motor is especially useful.- The problem of nishing the small pump cylinder bores to the accurate dimensions required can only be done satisfactorily by grinding. My improved pneumatic motor is designed to grind such openings at an eiicient grinding speed. The motor shown in the attached drawing has a normal operating speed of onephundred thousand revolutions per minute using a 3%; inch diameter wheel and operating under pounds of air pressure. A smaller sized motor is vbeing made which operates at 175,000 revolutions per minute under the same'air pressure. These high speeds are believed to be the result of improvements which form the subject matter 'of this application.

A further object of my invention is to provide a pneumatic motor of the class described in which the bearings are lubricated in an improved manner.

Still a further object of my invention isto provide a motor of the class described which will have an improved rotor construction and which will utilize the air Vsupplied to operate same in a more efficient manner than heretofore has been accomplished.

With these and other objects inv view, my invention consists in the arrangement, construction and combination of the various parts of my improved device, as described in this specification, claimed in my claims and illustrated in the accompanying drawing in which:

Figure l is a full-sized plan view of my improved motor construction.

Figure 2 is an enlarged sectional view, taken on the line 2-2 of Figure 1. y Figure 3 is a sectional view, taken on the line 3 3 of Figure 2, and

Figure 4 is a still further enlarged sectional view of the rotor portion of the motor illustrating the pathv takenl by the air in flowing through l thejmotor.

Referring to the accompanying drawing I have used' the reference numeral I0 to indicate a cylindrical housing, one end of which is threaded to receive a cap II. 'That portion of the hous-y ing .I0 adjacent to the cap II is formed with a relatively large bore I2 therein, while the bore I3 inthe other or front end of the housing` I0 is of smaller diameter. A bearing sleeve I4 is adapted to be pressed in the bore I3 and a pair of single row ball bearing assemblies l5 are pressed in the respective ends of the sleeve I4. An annular bead IE extends outwardly from the inner end of the sleeve I4 and a feltring I1 of rectangular cross-section is disposed in thebore I2 between the bead kI6 and the shoulder formed between the bores I2 and I3. The ring I'I is adapted to be saturated with oil when assembled and to form a .wick for lubricating the bearings, as will later be described.

The rotor of my improved motor comprises a shaft I8 which is mounted vupon the bearings I5. The end of the shaft which terminates within the bore I2 is formed integrally with a disc I9, periphery of which is formed integrally with a driving cylinder 20. housedwithin the bore I2 and is of a diameter sufhciently smaller than the bore I2 that an air passageway therebetween is provided. It will be noted that the shaft I8 projects through `the front end of the housing I0 and that the projecting end of the shaft is threaded to receive a nut 2l which may be threaded down to thus prevent end movement of the shaft relative to the bearings I5. 'A further function of the nut 2| is to impress an axial load on'the bearing assemblies just sufficient to take the end play out of the bearings. This is essential for high speed operation of all ball bearings.

y The projecting end of the shaft I8 is bored to receive the shank of the grinding wheel 22 and is slotted longitudinallyso that when a collet 23 is screwed down over theI end of the shaft the shaft will grip the grinding wheel shank as in a conventional chuck.

It willv be noted `from Figure 3 that the bore of the cylinder 2IJis formed of anannulus of saw-teeth 24, one edge of each tooth extending radially, and the other edge extending diagonally so as to connect the top of one tooth with the base of the adjacent tooth. These saw teeth extend sub-stantially the full length of the cylinder 20. The cap member II is provided with a central opening therethrough, and fitting 25 is secured by means of a nut 25. The fitting 25 is provided with a distributing head 21 which is disposed within the cylinder 20 and a needle valve 28 is screwed into opening -in the other end of the fitting.A The inner end'of the'head The cylinder 20 is The operation of my improved `motor is as` follows:

Air under pressure is admitted to the distributing head 2'! by means of the needle valve 28 and is directedpagainst the teeth 24 through the six openings 30. This causes the cylinder 22 to revolve. Inasmuch as repeated tests have shown this motor to be two to three times as efficient as similar motors having radially extending driving teeth, it is believed that the air after striking one tooth is forced against the periphery of the head and rebounds against a second tooth of the rotor. This operation is believed to be repeated until the air nally escapes from between the head and the rotor.

The path followed by the air is shown by arrow 3l in Figure 4. The air after leaving the rotor collects in the space between the cap ll and the large end of the cylinder 20. Three exhaust ports 32 are provided in the cap l l through which the major portion of the air is discharged. However, these ports sufficiently restrict the flow of air from the housing that a small but definite percentage ows forwardly between the cylinder 2B and the housing l, as shown by arrows 33. This portion of the air strikes against the felt ring Il'. The air rebounds from the felt ring and flows downwardly along the forward side of the disc la and enters the space between the balls of the inner bearing assembly I5. 'The air then flows forwardly along the sleeve lli and then through the outer bearing assembly l5. The air is discharged through an enlarged shaft opening in the forward end of the housing l0. An extremely important feature in connection with this motor is that the felt ring when assembled is saturated with oil and the air being directed upon the ring picks up minute quantities of the oil and conducts same to the bearing assemblies. In the high speed operation of` ball bearings great difficulty has been encountered in providing lubrication which will allow the bearings to operate at the high speed without burning up. If no lubrication is provided, chattering begins and the bearings soon fail. If, however, a relatively large amount of oil is provided, which in this case would be a single drop of oil, then the bearings will burn up, due to the great internal friction setup in the oil. It is essential for the successful operation of any bearing at speeds mentioned herein that only minute quantities of oil be deposited on the balls of the bearings. This can readily be demonstrated by applying a single drop of oil to a bearing of the size shown, while it is rotating at 100,000 revolutions per minute. As soon as the oil is applied the bearing will almost instantly turn blue with the excessive heat and of course fail. The applicant has provideda unique method of applying minute quantities of oil to the bearings by utilizing a small proportion of air required to operate the motor and directing this small portion of the air against an oil-fed wick and then directing the air to the bearing. As the outer surface of the ring l1 tends to dry out oil is immediately replenished by capillary action from the rest of the ring.

Among the many advantages arising from the use of my improved motor, it may be well to mention that this motor has a rotor of an eX- ceptionally low weight for the power developed. Furthermore, my improved rotor may be conveniently and economically machined to almost perfect dynamic balance.

Still further, due probably to the rebound air against a second tooth after it strikes one of theV rotor teeth, much more efficient operation of the motor is obtainable than is possible with other air motors of this character.

Some changes may be made in the arrangement, construction and combination of the various parts of my improved motor without departing from the spirit of my invention, and it is my intention to cover by my claims such changes as may reasonably be included within the scope thereof.

I` claim as my invention:

1. A device of the" character described comprising, a housing, a shaft rotatably mounted upon bearings within said housing, a driving member secured to said shaft within said housing, said member having an annulus of teeth thereon, an air distributing member secured to said housing 'adjacent to said driving member, said distributing member having an opening therein which directs air under pressure against said teeth to rotate said shaft, an oil saturated wick disposed within said housing, said housing having an exhaust opening therein through which a portion of the air escapes after it is discharged from said distributing member, there being a continuous passageway within said housing from said distributing member past said wick and through said bearings to the outside of said housing, the remaining portion of the discharged air escaping through said passageway, for the purpose described.

2. A device of the character described comprising, a housing, a shaft rotatably mounted upon bearings in said housing, the inner end of said shaft terminating within said housing while the outer end thereof projects outwardly therefrom, a disc formed on the inner end of said shaft, the periphery of said disc having a cylinder projecting axially therefrom and within said housing, the bore of said cylinder comprising an annulus f of saw teeth which extend axially along said bore, an oil saturated wick disposed within said housing, and an air-distributing head secured to said housing in position within said cylinder, said head having a diagonally extending opening in its periphery which directs the air from within at an angle against one side of each of said teeth, and said housing having an exhaust opening therein whereby a portion of the air escapes after it is discharged from said head, there being a continuous passageway within said housing from said distributing head past said wick and thru said bearings to the outside of said housing,v the remaining portion of the discharged air being directed against said wick and then escaping from said housing along said passageway, for the purpose described.

3. A device of the character described comprising, a housing, a'shaft rotatably mounted within said housing upon a pair of spaced bearing assemblies, one end of said shaft projecting outwardly from said housing, a cylinder secured to said shaft within said housing, the bore of said cylinder being formed of an annulus of .saw

teeth which extend axially along said bore, an oil saturated wick disposed within said housing, and an air-distributing head secured to said housing Within said cylinder, said head having a plu- 5 rality of diagonally extending openings in its periphery which direct air from within said head outwardly at an angle to the radial against the radial sides of said saw teeth, said housing having an exhaust opening therein through which a l portion of the air discharged from said head escapes from said housing, the remaining portion of the air from said head being directed against said wick and then escaping from said housing along a path through said bearings. l 4. A device of the character described comprising, a housing, a shaft rotatably mounted within said housing upon a pair of spaced ball bearing assemblies, one end of said shaft terminating within said housing and the other end 30 projecting outwardly therefrom, the inner end of said shaft having a cylinder formed thereon, the bore of said cylinder comprising an annulus of saw teeth which extend axially along said bore, an oil saturated ring disposed within said i5 housing between said cylinder and said bearings, and an air-distributing head secured to said housing within said cylinder, said head having a plurality of diagonally extending openings in its periphery which direct the air from within said l0 head outwardly at an angle to the radial against the radial sides of said saw teeth, said housing having an exhaust opening therein through which a portion of the air discharged from said head escapes from said housing, the remaining porl5 Ption of the discharged air being directed against said ring and then escaping from said housing along a path through said bearings.

5. A device of the character described comprising, a tubular housing, one end of which is ,0 provided with a bore materially larger than the bore in its other end, a bearing retaining sleeve secured in the smaller of said bores in said housing, said sleeve supporting the peripheries of a pair of ball bearing assemblies in the respective ,5 ends thereof, a shaft extending through said bearings and rotatably mounted thereby, the end of said shaft adjacent to said larger bore having a disc formed integrally therewith, the other end of said shaft projecting outwardly from said 0 housing, said projecting end being screw threaded, a nut threaded upon said shaft which produces an axial load upon said bearings, a cylinder formed integrally with the periphery of said disc, said cylinder projecting axially in a direction op- ;5 posite to said shaft. the bore of said cylinder comprising an annulus of saw teeth which extend axially along said bore. an outwardly projecting retaining member formed on the inner end of said bearing sleeve. a felt oil saturated ring dis- 0 posed within the larger of said bores upon said bearing sleeve in position between said retaining member and the shoulder formed in said housingr between said bores. and an air-distributing head disposed within said cylinder. said head having a 5 plurality of diagonally extending openings in its periphery which directs air at an angle against the straight sides of said saw teeth. said housing having an exhaust opening therein through which a portion of the air discharged from said head D may escape from said housing. the remaining portion of the air discharged from said head being directed along a path between said cylinder and said housing against said ring and then escaping from said housing along a path through 5 said bearing assemblies.

6. A device of the character described comprising, a cylindrical housing, a sleeve fixed within the bore of said housing, said sleeve having a pair of ball bearing assemblies mounted in the respective ends thereof, a shaft rotatably mounted upon said bearing assemblies, one end of said shaft terminating within said housing and the `other end projecting outwardly therefrom, the

inner end of -said shaft having a cylinder formed thereon, the bore of which cylinder has an annulus of saw teeth extending axially therealong, an oil saturated ring disposed within said housing between said cylinder and said bearings, an air distributing head secured to said housing within said cylinder, said head having a plurality of diagonally extending openings in its periphery which direct the air from within said head outwardly at an angle against the radial sides of said saw teeth, and said housing having exhaust openings therein through which a portion of the air discharged from said head escapes from said housing, the remaining portion of the air being directed against said ring and then escaping from said housing along a path through said sleeve and bearings, for the purpose described '7. A device of the character described comprising a housing, spaced ball bearings mounted Within said housing, a shaft mounted upon said bearings to rotate Within said housing, a driving member secured to said shaft in said housing, said member having an annulus of teeth thereon, an air distributing member secured in said housing adjacent to said driving member, said distributing member having an opening therein which directs air under pressure` against said teeth to rotate said shaft, an oil saturated wick disposed within said housing, said housing having two exhaust openings therein for the air leaving said teeth, the first of which communicates directly with the discharge side of said teeth and the second of which communicates with said discharge side only through said bearings, the parts being so arranged that air entering said device picks up oil from said wick and that portion which is discharged through said second mentioned exhaust opening deposits a portion of the oil carried thereby upon said bearings.

8. A device of the character described comprising. a housing, a pair of spaced bearings mounted in said housing, a shaft mounted upon said bearings to rotate within said housing, a driving member secured to said shaft within said housing, said member having an annulus of teeth thereon. an air distributing member mounted within said housing. said distributing member having a hat di sc-shaped chamber therein and having a central opening therein through which air enters said chamberI said distributing member also having a plurality of discharge openings around its periphery which directs the air under pressure against said teeth. said housing having two exhaust openings therein through which air from said driving member is simultaneously discharged to the outside atmosphere. the rst of said openings communicating directly with the discharge side of said teeth so that air may ow directly from said teeth to the outside. While the second communicates with the discharge side of said teeth only through said bearings. and an oil saturated member disposed within said housing, whereby the air which operates said motor picks up oil from said saturated member and deposits same upon said bearings before being discharged from said second-mentioned exhaust opening.

EMORY J. MONNIER. 

